Process of manufacture of a new kind of parchment-paper.



'UN TTED STATES PATENT ()FFTCE. I

ERNST FUES, OF HANAU', GERMANY.

PROCESS OF MANUFACTURE OFA NEW KIND OF PARCHMENT-PAPER.

No Drawing.

To all 10/10/12 I? may concern Be it known that I, .Enxs'r Furs, a subject of the German lhnperor, and resident of 1lamul-on-thc-l\lain, (tel-many, have invented certain new and useful Improvements in the Process of Manufacture of a New Kind of Ia-rchment-Iaper, of which the following is a. specification.

Hitherto only one method of manufacturing parchment paper has been known, which consists in causing concentrated sulfuric acid of from 59 to 61 Baum ,(or a cxmcentrated solution of zinc chlorid) to act on paper, papers made from cotton yielding the best results. i

I have found that an equally valuable parchment paper can be produced ata very reduced cost and with less danger to the operatives by using very dilute acids, organic acids, acid salts and such salts as act in a like manner through dissociation in dilute aqueous solution with, or without, the addition of formaldehydes, such substances 7 being employed at a high temperature either in the course of manufacturing the paper, or after has been made. In the latter case the raw paper which is used in the process :an beof varied composition, the so-called imitation parchment paperor greaseproof paper of the so-called Mitscherlich-cellulose made from hard boiled cellulose by grinding to an unctuous or viscous consistency being the most suitable for the purpose in view.

In carrying out the invention the paper is soaked in the aforesaid acid solution and then' dried at a temperature of about 100 Centigrade for instance on drying cylinders such as are generally used in the manufacture of paper.

If the parchmentizing of the paper is to be effected on the paper machine, the parchmentizing preparation must be of a strength adapted to the amount of moisture in the paper stuif at its point of application.

After the paper has been dried, it possesses, according to its composition and preliminary treatment, a more or less pronounced parchment-like constitution and resistance to the action of water.

Imitation parchment paper or greaseproof paper will be thoroughly parchmentized in accordance with the process I It is conspicuously hard and when. viewed through presents an appearance more devoid of structure than has been hitherto obtained by the grinding Specification of Letters Patent.

Patented July 23, 1912.

Application filed November 20, 1911. Serial No. 661,267.

process already described. Both these features and its resistance to the disintegrating action of water and its great power of re sisting acids and alkalies characterize the parchmentized imitation parchment paper normal, but with the simultaeous employment-of formaldehyde, an acid having l/20th the strength of normal sulfuric acid will sufiice to produce a perfect parchmentized paper.

Organic acids exercise on similar raw n'iaterial a parcl'nnentizing action, which however is less pronounced when formaldehyde is not present than when formaldehyde is used in conjunction with the organic acids. For instance by the action of 10 per cent. acetic acid and 0.6 per cent. formaldehyde, a very good parchmentization of the imitation parchment paper or greasepr'oof paper is obtained following the hereinbefore described mode of treatment. An essential condition is however that the paper should always be treated at a high 1 temperature.

- The process is equally effective whether the paper-under treatment be sized, or not. Formaldehyde can of course be replaced by its polymerization and addition products, as well as by compounds which, when suit-- ably treated, decompose and liberate formal-- dchyde and such substances are to be understood-as included under the term formah dehyde employed in the claims hereof.

The acid remaining in the paper after parchmentization can be washed out or neutralized and rendered harmless in any suit able manner.

The present process differs from the usual parchment-izing processes by means of concentrated sulfuric acid in the following respects: 1. Instead of concentrated sulfuric acid of 59 to 61 Baum only thoroughly diluted acid substances are employed, such for instance as a sulfuric acid of not more than l/ 10th normal strength. 2. Instead of sulfuric acid, volatile mineral acids such as hydrochloric acid and organic acids are used together with formaldehyde. .3. Acid and other salts which are excluded entirely in the old process of manufacturing parchment paper, such'for instance as sulfate of alumina, or bisulfate, can be used in this process with success. 4:. Whereas for the manufacture of parchment paper by means of sulfuric acid, pure cotton raw material having as high an absorption power as possible is preferably used, this same raw material,

if not subjected to a preliminary treatment,

is quite useless for the new process; moreover imitation parchment paper or greaseproof paper is suitable as the raw material for the present process, whereas, on account of, its special density and small absorption power, it was totally unfit for the manufacture of genuine parchment paper, by means of concentrated sulfuric acid. '5. A high temperature of about 100 centigrade is requisite for carrying out the process.

The new process offers, when compared with that hitherto in. use, a considerable improvement as regards economical working,

' as in consequence of the employment of cheaper raw papers and cheaper chemicals,

especially when the paper is produced at one operation on the machine, a considerably cheaper production of parchment paper is obtained as compared with the old process.

In addition to this, the-present process has the further advantage over the former process that it employs substances which are less two subscribing witnesses.

injurious to the health of the operatives than those hitherto used.

I claim: ,1 1. The hereindescribed improvement in the process of manufacturing parchment paper comprising treating suitable raw material with a highly diluted acid solution at a temperature of about 100 C.

2. The herein described improvement in the process of manufacturing parchment paper comprising treating suitable raw material with an acid solution and formaldeterial with an acid solution and formaldehyde at a temperature of about 100 0..

4. Parchment paper produced acidsolution at a temperature 0 about 100 C. and which paper is relatively hard and adapted to resist in'a marked degree the disintegrating action of water, acids and alkalies.

5. Parchment paper produced by treating suitable raw material with an acidsolution and formaldehyde, said paper being relatively hard, translucent, fected by water, acids or alkalies.

In testimony whereof I have signed my name to this specification in the presence of ERNST' FUES.

, Zitnesses:

FRANZ HAssLAsHnR,

ERWIN DIPPEL.

by treating suitable raw material with a highly diluted and not readily af- 

